ObjectivesA drug that improves survival and/or disease progression can create real option value (ROV)—the additional health gain from future innovations enabled by a longer survival. ROV can be a relevant consideration for both clinical and payer decision-makers. We aimed to estimate the ex ante ROV for first-line (1L) alectinib in anaplastic lymphoma kinase (ALK)-positive non-small-cell lung cancer (NSCLC).MethodsWe developed a Markov model to estimate life-years (LYs) and quality-adjusted life-years (QALYs) gained with 1L alectinib versus 1L crizotinib due to potential future second-line (2L) drugs. Transition probabilities were derived from the phase 3 trial of 1L alectinib and phase 2 trial of 2L brigatinib. We identified drugs being studied in phase 2 and 3 trials in ALK-positive NSCLC at the time of alectinib’s 1L approval and projected the likelihood and timing of their arrival and their potential efficacy based on publicly available data.ResultsThe discounted incremental LYs and QALYs for alectinib increased by 12.9% (95% CR − 2.96%, 34.82%; 1.25 vs. 1.11) and 11.2% (95% CR − 2.14%, 29.29%; 1.03 vs. 0.92), respectively, after accounting for ROV. The incremental ROV of alectinib was sensitive to the projected efficacy of future drugs, uptake level, and the hazard ratio of progression-free survival of alectinib (vs. crizotinib).ConclusionsEx ante ROV can be a significant value consideration in therapeutic areas with high levels of expected innovation. The potential efficacy of future drugs and incremental survival with alectinib at the projected time of arrival are important considerations in assessing ROV.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40273-022-01147-5.